So, it turns out that ABCL doesn’t support resuming from arbitrary stack frames, but it does support restarts in general. For example:
(defun prompt-new-value (prompt)
(format *query-io* prompt)
(force-output *query-io*)
(list (read *query-io*)))
(defun high ()
(format t "High~%")
(middle '(1 2 3 4 5 6)))
(defun middle (items)
(format t "Middle~%")
(loop for item in items
do (low item)))
(defun low (item)
(if (= item 4)
(restart-case (error "Oh my god, a 4.")
(use-value (value)
:report "Anything but a 4!"
:interactive (lambda () (prompt-new-value "Number: "))
(low value)))
(format t "~A~%" item)))
calling (high) and interactively passing a 9 to the restart yields:
High
Middle
1
2
3
9
5
6
#commonlisp